. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIGURE 1. (a) A diagrammatic representation of the head of a cockroach showing the -~ square "window" made by removing a piece of cuticle from the front directly above the protocerebrum (Br I), thus allowing access to the pars intercerebralis (PIC), (b) Frontal view of the brain under the window illustrating the removal of the part of the brain containing the pars intercerebralis (white area). PIC: pars intercerebralis, Br I: protocerebrum, Br II: deutocerebrum, OpL: optic lobe, OpT: optic tract, AN : anten
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIGURE 1. (a) A diagrammatic representation of the head of a cockroach showing the -~ square "window" made by removing a piece of cuticle from the front directly above the protocerebrum (Br I), thus allowing access to the pars intercerebralis (PIC), (b) Frontal view of the brain under the window illustrating the removal of the part of the brain containing the pars intercerebralis (white area). PIC: pars intercerebralis, Br I: protocerebrum, Br II: deutocerebrum, OpL: optic lobe, OpT: optic tract, AN : antennal nerve. area. Since the brain is a soft, yielding structure, surgical ablation of this area was also not completely satisfactory. However, the cockroaches survived for long periods post-operatively and the extent of surgery could be easily checked by histo- logical methods. Usually the first cut and removal of one side of the pars inter- cerebralis were easier than the second cut and removal of the other side. The areas immediately beneath the indentation of the pars intercerebralis, where the medial neurosecretory cells are located, were especially difficult to remove without damag- ing the area where the nerve tracts of the medial neurosecretory cells cross. Al- though notation of "complete" or "incomplete" ablation was made by the operator, histological confirmation was required, especially in those cockroaches which re- established a normal rhythmic pattern post-operatively. Histology of the brain of cockroaches showing arrhythmicity after surgery was also important. Since some operated cockroaches remained arrhythmic for 3 weeks before they resumed normal rhythmicity, long-term observation was required to establish clearly post- operative arrhythmicity. Therefore, most of the arrhythmic animals were kept until they died. After the effect of surgery on the rhythm had been assayed by recording the animal's activity for many days, the brains of most ani
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
